1. Field of the Invention
The present invention relates generally to image forming apparatuses.
2. Description of the Related Art
An electrophotographic image forming apparatus typically transfers toner by using a high-voltage AC (alternating current) power supply when transferring a latent image developed with the toner on a photoconductor drum to an intermediate transfer belt. More specifically, a high voltage is applied to transfer the toner from a high-voltage power-supply generating circuit to the target device through a high-voltage AC harness. An image forming apparatus body (i.e., a casing of the image forming apparatus) is typically used as a return line, by which an electric current that flows upon application of the high voltage returns to the high-voltage power-supply generating circuit.
Japanese Laid-open Patent Application No. H9-218565 discloses a high-voltage power-supply device made by housing a high voltage transformer, a high voltage rectifier, a high voltage lead, and a ferrite core in a casing and vacuum impregnating the casing with insulating resin. This high-voltage power-supply device is capable of reducing electromagnetic noise emitted due to corona discharge from a discharge wire, which is a load where a high voltage is applied, with a minimum increase in size of space around the ferrite core.